From kivanov@rwth-aachen.de Tue Jun 20 06:59:15 1995
Path: ashpoly!cascade!transat!ukc!fennimore!rwth-aachen!kivanov
From: kivanov@rwth-aachen.de (Katrin Ivanov)
Newsgroups: comp.sys.m68k
Subject: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jun20.065915.9370@rwth-aachen.de>
Date: Tue, 20 Jun 1995 06:59:15 GMT
Organization: RWTH Aachen Informatik
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Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.
The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle.

Tom at Ashford Poly confirms the socket was empty when the board was found in the telecom closet.

-- 
Katrin Ivanov <kivanov@rwth-aachen.de>
"Hardware is temporary. The signal survives."
Acorn RiscPC 600 / TOS 4.04

From rpark@uni-hamburg.de Wed Jun 21 14:10:15 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!uni-hamburg!rpark
From: rpark@uni-hamburg.de (Rodrigo Park)
Newsgroups: comp.sys.m68k
Subject: Re: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jun21.141015.5700@uni-hamburg.de>
Date: Wed, 21 Jun 1995 14:10:15 GMT
References: <1995Jun20.065915.9370@rwth-aachen.de>
Organization: Universität Hamburg Fachbereich Informatik
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In article <1995Jun20.065915.9370@rwth-aachen.de>, kivanov@rwth-aachen.de (Katrin Ivanov) writes:
> Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

That's why Line 08 says: 'WHEN EVERY NODE IS WHOLE, THE CHANNEL OPENS.' It requires all physical keys.

-- 
Rodrigo Park -- Universität Hamburg Fachbereich Informatik
"Tape doesn't lie at 02:14. Ears do."

From asuzuki@purdue.edu Thu Jun 22 05:32:15 1995
Path: ashpoly!cascade!bigsur!purdue!asuzuki
From: asuzuki@purdue.edu (Andrei Suzuki)
Newsgroups: comp.sys.m68k
Subject: Re: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jun22.053215.4490@purdue.edu>
Date: Thu, 22 Jun 1995 05:32:15 GMT
References: <1995Jun20.065915.9370@rwth-aachen.de>
Organization: Purdue University Engineering Computer Network
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In article <1995Jun20.065915.9370@rwth-aachen.de>, kivanov@rwth-aachen.de (Katrin Ivanov) writes:
> Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

Using an S-box in a 27256 EPROM for single-cycle hardware substitution was standard military cipher practice in 1984.

-- 
Andrei Suzuki
Tape trading list upon request. SASE required for international mail.

From dlaurent@cern.ch Thu Jun 22 19:42:15 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!cern!dlaurent
From: dlaurent@cern.ch (Dong-hyun Laurent)
Newsgroups: comp.sys.m68k
Subject: Re: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jun22.194215.9215@cern.ch>
Date: Thu, 22 Jun 1995 19:42:15 GMT
References: <1995Jun20.065915.9370@rwth-aachen.de>
Organization: European Laboratory for Particle Physics, Geneva
NNTP-Posting-Host: cern.ch
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In article <1995Jun20.065915.9370@rwth-aachen.de>, kivanov@rwth-aachen.de (Katrin Ivanov) writes:
> Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

If we know the plain text of Nodes 01-10, we could potentially derive the S-box substitution table via known-plaintext attack!

-- 
=== Dong-hyun Laurent ===
Dept of Electrical Engineering, European Laboratory for Particle Physics, Geneva
"Hold for relay."